In short-period usage absorbent articles such as daytime diapers, light, thin and flexible materials are especially desirable to provide improved freedom of movement and increased comfort for the wearer. Therefore, it is preferred to apply materials like polymeric films or nonwoven webs with very low basis weights.
However, a drawback of a disposable article using very low basis weight materials is that these materials have an increased tendency to be translucent. It is difficult to manufacture thin materials, which provide a desired degree of opacity, because only a limited amount of whiteners, such as titanium dioxide, can be added without receiving materials, which are brittle and tend to disintegrate easily.
The problem of translucency in light, thin, and flexible absorbent articles is further increased by the fact, that such articles may comprise regions with only very few overlying layers of material. For example, in a diaper the use of a thin and relatively small absorbent core results in a relatively large area in the front and/or rear waist region of the diaper, which only comprises a topsheet and a backsheet overlying each other.
While light, thin and flexible diapers with improved freedom to move are highly appreciated by the consumer, translucency is usually disliked by the wearer or caretaker. The skin of the wearer is shining through the diaper in some areas and moreover, the structural features inside the diaper, like for example elastics or parts of the absorbent core, can be seen from the outside due to thin covering materials. Hence, the diaper tends to get a rather patchy appearance.
The above-said becomes even more problematic, when the diaper is soiled and the stains of the absorbed exudates shine through, due to a thin absorbent core and a light, translucent backsheet.
It is thus an objective of the present invention to provide a light, thin and flexible absorbent article with an improved outer appearance without the need to employ economically unattractive materials.
It is a further objective of the present invention to provide a light, thin absorbent article, which looks like an undergarment, especially for use as a daytime diaper.
Color-printed materials for use in absorbent articles are well known in the art:
WO 99/60973 filed May 28, 1998 entitled “Clothlike, breathable backsheet with multicolored graphics for disposable absorbent article” discloses absorbent articles with a backsheet comprising a microporous polymer film printed with multicolored graphics and a nonwoven material laminated to the film. The microporous film has a “b” value from 0.0 to 0.5 and less than 4% thermal shrinkage at 50° C. and 50% relative humidity for one week.
WO 99/32164 filed Dec. 19, 1997 entitled “Disposable absorbent articles comprising microporous polymer films with registered graphics” relates to absorbent articles with a backsheet comprising a microporous film printed with a registered graphic and comprising by weight 30-60% polyolefin and 40 to 80% calcium carbonate. The microporous film has a “b” value from 0 to 5 and less than 2% thermal shrinkage at 50° C. and 50% relative humidity for one week.
One drawback with printing is, that printing large areas of the backsheet becomes expensive and thus, is not economically attractive. Moreover, to receive intense colors, high amounts of ink have to be applied, which—besides raising expenses—may lead to the rubbing-off of ink during use of the disposable article.
Besides printing, other techniques to improve the appearance of materials for use in absorbent articles have been developed:
WO 93/19714 filed Mar. 22, 1993 entitled “Multilayer film exhibiting an opaque appearance” discloses a mulitlayer film comprising two outer layers and a central polymeric layer. The central layer has high concentrations of pigments or other fillers to increase the masking ability. The central layer may be whitened or colored. However, due to the number of layers, the multiplayer film is rather thick and thus not very suitable for use in a light, flexible diaper.
WO 96/10380 filed Aug. 4, 1995 entitled “Laminate material and absorbent garment comprising same” refers to a laminate material with a first layer having opaque areas, transparent areas and a coloration and a second layer having a different coloration than the first layer. The coloration of the second layer is visible through the transparent areas of the first layer to a greater extent than through the opaque areas of the first layer.
EP 1 252 873 A2 and EP 1 247 508 A2 both filed Apr. 4, 2002 and both entitled “Discreet absorbent articles” disclose absorbent articles comprising a pigmented cover, a pigmented apertured transfer layer and a pigmented backsheet, which provides masking of synthetic menstrual fluid and discretion.
WO 00/38915 filed Dec. 29, 1999 entitled “Pattern embossed multiplayer microporous films” discloses a multilayer film with first microporous layer having at least 35% filler and second microporous layer having at least 35% filler and a coloring agent. The fist and second layer are continuously joined together and have embossed and non-embossed regions wherein the embossed regions color-contrast with the non-embossed regions.
However, all those techniques are rather complex and thus expense. Furthermore, they tend to require materials with high basis weight due to the need for several layers, which generally is disliked in a light, highly flexible absorbent article.
Thus, it is a further objective of the present invention to provide multicolored absorbent articles, which are thin, light and highly flexible due to use of thin materials with low basis weight.
These articles should at the same time provide an attractive outer appearance, provide improved freedom of movement and increased comfort for the wearer and allow the use of economical attractive materials.